Cod sursa(job #305887)

Utilizator mihaionlyMihai Jiplea mihaionly Data 18 aprilie 2009 19:57:59
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.32 kb
Raporteaza aceasta sursa 
#include <stdio.h>
FILE *f=fopen("ciur.in","r");
FILE *g=fopen("ciur.out","w");
long n,nr=1;
bool ok[2000001];
int main()
 {
 int i,j;
 fscanf(f,"%d",&n);
 for(i=3;i*i<=n;i+=2)
  {
  if(!ok[i])
   {
   nr++;
   ok[i]=1;
   for(j=3*i;j<=n;j+=2*i)
    ok[j]=true;
   }
  }
 fprintf(g,"%d",nr);
 return 0;
 }